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From:   David Howells <dhowells@redhat.com>
In-Reply-To: <20191003014310.13262-1-paulmck@kernel.org>
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Subject: Re: [PATCH tip/core/rcu 1/9] rcu: Upgrade rcu_swap_protected() to rcu_replace()
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Date:   Thu, 03 Oct 2019 09:39:17 +0100
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paulmck@kernel.org wrote:

> +#define rcu_replace(rcu_ptr, ptr, c)					\
> +({									\
> +	typeof(ptr) __tmp = rcu_dereference_protected((rcu_ptr), (c));	\
> +	rcu_assign_pointer((rcu_ptr), (ptr));				\
> +	__tmp;								\
> +})

Does it make sense to actually use xchg() if that's supported by the arch?

David